Automatic voltage-regulator system.



G .A- BURNHAM.- AUTOMATIC VOLTAGE REGULATOR SYSTEM.

APPLICATION FILED AUG.23,1909..

Lllfifi ge i Patented N0v.24, 1914.

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, iec cetjion of Letters fetexit. Patented New, 24, 19:34,

I 4 ""A jueam 'file-anu ust 2a, woe. Serial No. 514,122.

'To-all whom it may concern. I

Be it known that I, GEouoE A; Benin-1AM,- a citizen of the UnitedStates, residing at .,-Essex, in the county. of Essexene State ofMassachusetts, have invented an Improve- :ment in AutomaticVoltege-Reguiator-Systems,of which the following descriptiomfiinconnection with "the" accompanying drawings, is a specification,likeletterswon:the

drawings ,reprejsenting lil're' parts: v

My inventions an 1' iproi en'i'ertt inuuto- 5 i matic voltage regulatorsystenis for use with alternating current,'having for its Object-theprovision of aummtiemeans for regulating the voltage at I the bus-hersorgietthe center i of distribution-( ron one? rse' ver2tl' of the feedercircuits in accordance with predetermined characteristics? Forinstiin'ce, in

large plants it is necesssryto hat'e provision for maintaining thepi es'surejatthe end of the feeders constant and prov1siQ1l-for-regulatingthe feeder circuit its desired "for any given load, and for inde'iendently regulat ing a'plurality of feedersfroin'the'szimebusbarsWithout varying 'the' bus-bar i'voltage.

Accordingly my presenti-rivention consists in providing means ijor ccmTJli's'h'ing tlig ob ects automaticallyfi T he more specificohjectsihnd; advantages of the present invention will he pointedout 7-niore at length in thecours of the follow ing description of-theconstructionel'details and operation, taken LllCOnllBGtlOil with theaccompanying illustrative the preferred embodiments, i

In the drawings, I hztvesh'own'd disgrmw matic View of thepreferred;-einhodiinent of my invention. i

The transmitting circuit 1, 2, is connected by a; switch 3 with thebus-bars, or source of energy 4, 5, which herein represent a single-,phase system or "any tw dhu's-bars of the standard polyphase systems ofdistribution, the load or translating devices-being honventionallyindicated tit-'6; Inserted in one -nun1ber thereof connectedwith thesaidhushers. As the load 6 varies, the voltage at 6. will vary, andhence to maintain it uniform I vary. the voltage of the transformer 7,

side of the service"Wires"Z1, 2,-; is e trans former 7, whose lowpotential or secondary circuit winding 8 is designed'to carry the entirecurrent of the circuit, and Whose-high potential or primary or supplycircuit Wl11(l-' ing is divided into a plurelityfo'f parts, preii,erably two, 9, 10,:1sshowh in this preferred embodiment. The part -9isconnected 'per- ,manently across the circuit by Wires 11, 12,

the former beingshown as connecting" to the Wire 1 and the latter to theWire 2, a switch 'ing also in series with the Wire 12. herein. shown theregulatorlfi is in the form of a cylinder having e portion. 24 ofconductive inateriel'and e portion 25 Of lIlSll'r, leting material.meter 26 is used to control the brush movement by suitable means, suches megnets 27,

drawings of: v

" gby a Wire 38 from the hzittc" energy @111 practice, let it besupposed that 4-, '5, represent e set of bus-burs in a station and thatone or more feeder circuits 13 being preferably interposed as shown. Theportion 10 of the transformer isconnected-by conductors 14, 15, to aregulating device 16 of the hind set forth iii-my application Ser; No.wlSSJQS filed March 23, 1909,

and shown as driven by it uiotorlS engaged by a brush 17 WlllCAconstitutes the terminal 0t thewlre 14-, the wire 15lOElIlg'fiOllllSClifiCl at 18 to the conducting portion of theregulittOlL. 4 Preferably a condenser 20 .is conn'ected ecr o'ss thecircuit 14-, .15, by wires 21,

'22, and a resistance or impedance coil 23,

is interposed in the Wire 15, said Wire 15 be- A contectmmlring volt-28, said voltmeter being preferably excitedby two currents, one derlvedfrom a ,po-

tentiel transformer 29 across the circuit 1, 2,:tnd the other from itcurrent transformer 30 herein shown as in the'wlre 2, the needle 31making contact with the points 32 and 33in accordencewith predeterminedarie -t1ons 1n the excit ng current and potential of the voltmeter. Theneedle3l is connected by ewire to esource otenergy 35 and the contacts82, 33, by w re 36, 37, to the solenoids 2T, 28, which govern the 'move;-1ne11t of the contact 17 of the regulator 16,

the! circuit of said solenoids being con'ipleted or source of therefromare to be independently controlled in accordance with my S YSiJGIl1,Ltl1Q feeder circuit .2 being a typical circuit, 1t being unregulatein the station) irrespective of the which transformer is connected inseries #i ith the line. The voltage of they trans former T is variedautomatically by short ,circuiting preferably one portion, of the "andas the regulator J 29, 30, in the feeder circuit, its needle 31 iscorrespondingly moved in one direction or the other so as to energizethe regulator controlling means 27, 28, and thereby correspondingly varythe periods of interruption L of the short circuit in the transformer 7.If

the contact 17 of the regulator moves to the right l i g. 1 the durationof the short circuit will be relatively short, whereas if it moves tothe left the duration of the short circuit will be relatively long. Asthe operation of this type of regulator is well understood itself .isnot herein claimed, it is deemed unnecessary to explain the samefurther, the application thereof or of an equivalent relay device to thesystem and in the combination herein explained constituting myinvention, whereby the control of the feeder circuit is renderedautomatic as distinguished from the hand control heretoforepractised.

In the preferred construction the high potential side of the boostertransformer 7, or preferably a portion thereof, is short circuitedthrough a resistance or impedance 23, causing a variation in theboosting effect of the high potential side of the booster transformer,the length of time of said short circuiting and hence the extent of saidvaria-' tion being dependent on the position of the brush 17 of theregulator in accordance with the voltmeter which automatically con trolssaid regulator, and as said voltmeter is automatically responsive tochanges in the feeder circuit. itself, it will be evident that theentire regulation is thereby automatic.

,The switch 13, preferably not automatic, *when thrown in one position,causes the automatic regulating apparatus to boost, and

i when thrown in the opposition position to buck, the voltage suppliedby the generator.

A change of potential in the feeder circuit effects the transformer 29of the voltmeter, and a change "-in current in the feeder circuitaffects the transformer '30 of said voltmeter, so that whenever thefeeder circuit varies, the voltmeter automatically closes the controlling circuit for shifting the contact 17 of the regulator 16 eitherto the right or to the left, thereby decreasing or increasing, as thecase may be, the duration of the short circuiting intervals of thecircuit of the high potential side of the booster transformer 7. Theboosting transformer 7. having a potential. winding 9 as primary and asecondary in series with one of themains,

will give a boosting effect according to the ratio of its primary andsecondary turns. The section 10 connect-ed through a resistance 23, therotary cylinder and its brush 17 will raise or lower the voltage of thefeeder circuit in iccordance with the load. The amount of boost willdepend on the ratio of turns of coils -9 and 8 and by shifting theswitch 13 the transformer may be made to buck the main voltage. Now, thesection 10 of the'transformer if opened or closed'at intervals bythe-compensating regulator will vary-the boosting-effect. If thesecondary 10 be opened the effect on the line voltage is the same asthat of an ordinary potential transformer. There will then be induce Tthe secondary 8 a certain potential depot ing on the ratio of turnsof 9to 8; If we short-circuit the winding 10 on itself :we

would have, neglecting Winding 8, a. one to one transformer withthesecondary shortcircuited. This means that in winding 10 current willflow 180 displaced from that in winding 9, and neglecting the loss intrans formation between 9 and 10, there would be practically, no flux inthe transformer core. In other words the two flux components would beequal and opposed, and winding 8 would not be cut by any lines of force,there by resulting in Zero potential acrossthe terminals. This is notrigidlytrue' on account of leakage, and in fact a certain potentialwould be induced in winding 8. a resistance as 23' be included in theshortcircuite'd section 10, as illustrated, therewill be a diminution.of current in saidsection,

o if and the ampere turns of winding 10-will be considerably less thanthose of winding 9, thereby resulting in an effective resultant fluxcutting winding 8 and inducing in said winding a potential depending onthe flux threading this winding. If contact 17 is shifted by thevoltmeter to insulating section 25 of the regulatonthe circuitof thecoil 10 will be opened, resulting in a'max-imum flux in the-core S and amaximum potential, on coil 8; i This may seem contrary to the theory ofthe ordinary constant potential transformer, but it must be r'ememberedthat the amount of current in winding 8 is not a function of that whichflows in winding 9, but is determined by, the load 6, whereas in aconstant potential transformer connected in the usual way the amount ofcurrent passing through coil 8 would be related directly to that whichis consumed in theprimary and directlv controlledby it. 'llherefore,when secti on 10 is short-circuited, it is clear that the potentialacross winding 8 will drop. The movement of contact 17 being controlledbythe \'oltmete1-"26', the

potential across the feeders 1, 2 can be held constant or variedaccording to prcdeten mined conditions. i

I. have herein set forth the best explanation of the operation of myapparatusl can present, but I do not desire to be limited to anyparticular theory of operation. The reactions in a transformer ofthekind herein shown where a coil in series with the line 1,1isje3a y 3'carries the entire load 'currentis very comple-X, and the factors varygreatly with varying load conditions. The fact remains, how ever, thatin the apparatus-I have-shown 5 and described the voltage is regulatedauton'iatically by the operation of the apparatus and proper regulationis maintained. In practically operating the apparatus I employ aboosting transformer in which the windings 9 and 10 have an equal numberof turns, as indicated diagrammatically. It will be understood that eachfeeder circuit from the bits-bars 4, 5, is providedwith a similar setor" automatic controlling apparatus.v In other Words, my inventionprovides automatic means to raise or lower the voltage of theindividualfeeders irrespective of the voltage of the generatoreircuit orbus'ba'rs, said raising or lowering of the voltage being accomplished byvarying the magnetic flux in the regulating transformer of said circuitby causing automatically the periodic variation of the current flowingin the transformer in accordance withthe variations in the load.vInstead of definitely changing the flux inthe transformer by definitepredetermined changes in, the current flowing through the transformer, fas by means of an automatic switch for cutting a out sections of thetransformer or by means which varies the relative positions of the coilsof the transformer so as to vary the leakage ,J' factor thereof, Iprovide means which maintains a continual variation of the twocomponents of the flux and simply Y changes the length of saidvariation, to accomplish the desired end. By this means is varied thetime element of the make intervals with relation to the time element of40 the ,break intervals, whereby the extreme fluctuations are varied byvarying the relative duration or time element of said tWo sets ofintervals. One of its most strikingv advantages may be explained asfollows: As the constantly operating regulator (of my type or theflirrill type, for instance,) necessarily'caus'esfa continual extremefluctuation of the voltage in the transformer because of its rapidsuccession of short circuiting and open-circuiting operations, causing arise of voltage during one operation and a fall of yoltage during theother operation, both (said rise and fall being actually greater than 3theoretically necessary, in order that the 5 mean. results shall becorrect, extreme sensitiveness is secured. The practical result isthatthereby I am enabled to effect the changes inthe voltage of thetransformer more nearly instantly or simultaneously with the changes inthe load than is possible by the means above mentioned. By providing:means which keeps up a constant set of extremes of electric fluctuationin the voltage of the transformer, the sluggish action of the magneticfluctuation is largely comclaim as new and desire to secure by Lettersresponsive to variations in the electrical con- ;Lsaid last mentionedcircuit for intermitpensated or overcome so that changes in the voltageof the transformer may be considered as practicallyinstantaneous; Thisproduces therefore an instantaneous response in the electric current asrequired in orderto maintain the voltage at therend of-the feeder lineconstant' with varyingload's.

'Having described my invention, what; I

Patent is, 1. In an automatic voltage regulator sys- 1 term, atransformer having a winding in series with the line, a potentialWinding across the line, and a voltage regulating-winding automaticallyputon closedcircuit during intervals of varying duration in accordancewith changes of line voltage. 2. In an automatic voltage regulatorsystem, a regulating transformer and its loadcarrying circuit, andautomatic means periodically to vary the primary current in saidtransformer in accordance with the variations in the load. I 3. In anautomatic voltage regulator system, a regulating transformer and itsload carrying circuit, means for producing in said transformer acontinuous rapid variation of flux, other than that produced by thenatural periods of said circuit, said means 1 being responsivetovariations of load in said circuit for changing the components of'theeffective flux. r

at. In an automatic voltage regulator system, a regulating transformerand its loadcarrying circuit, an auxiliary transformer, winding,continuously operating short circuiting means for intermittingly Varyingthe current of said winding and means responsive to the variationsinsaid load for regulating the durations of the variation intervals ofthe auxiliary Winding. I

5.In an automatic voltage regulator system, a'transformer having awinding in the load carrying circuit, a regulating winding ditions ofthe load circuit, and means for rendering the winding periodicallyeffective through intervals of varying duration. 6. In an automaticvoltage regulator system, aregulating transformer having pri-' 5 maryand secondary circuits, one circuit contaming a load, apotent1al circuitacross the line and impedance means in a' third circuit, and shortcircuiting mechanism acting on 129 tingly varying the primary andsecondarycomponents of the magnetic flux in the transformer inaccordance with the variations of load in the other circuit. I,

7 'In an automatic voltage regulator sys- '135 tem, a regulatingtransformer, one circuit v containing a load, a regulating circuitcontaining impedance, and short circuiting mechanism acting on'said lastmentioned circuit for intermittingly varying it'sfiirciiit me throughsaid impedance in accordancewith for controlling the duration of theshort the variations of load in the other circuit. circuiting responsiveto the electrical condi- 8. In an automatic voltage regulating systionsin the load circuit.

' tem, the combination of a supply circuit, a s In testimony whereof, Ihave signed my 7 ,5 load circuit, a regulating transformer comname tothis specification, in the presence 15 prising a winding in series inthe load cirof two subscribing Witnesses.

cuit, a winding connected'to the supply cir- GEORGE A. BURNHAM. cuit,and an auxiliary Winding adapted to Witnesses: be intermittentlyshort-circuited to regulate C. C. BADEAU,

10 the voltage of the series Winding. and means A. L. HORTON.

